BOSTON — Middle-aged women who enjoy an alcoholic drink every day may live longer, US scientists said Wednesday.

A major study by researchers at the Harvard School of Public Health in Boston found that women over 50 who consume a single alcoholic drink five to seven days a week are more likely to enjoy good health in old age than non-drinkers or those who had more than two drinks daily.

The study, involving 14,000 female nurses since 1976, found that those who consumed two alcoholic drinks every day were 28 percent more likely to improve the odds of “successful ageing,” while this increased to 50 percent for those who enjoyed just one alcoholic drink per day.

Dr. Qi Sun, the study’s lead author, wrote in the journal Public Library of Science Medicine, “Moderate alcohol consumption was associated with modestly better overall health status.”

The scientists defined “successful ageing” as living to at least 70, being free of cancer, heart conditions and other chronic diseases, and suffering no significant mental or physical impairment.

Experts were cautious about welcoming the findings and said that while the study offered some indications of the benefits of drinking small amounts of alcohol regularly, it could not justify anything beyond very modest levels.